1. Technical Field
The present invention relates to a wiper device.
2. Related Art
In Japanese Patent Application Laid-Open (JP-A) No. 2003-54375 (Publication 1) there is a description of a wiper control device equipped with a switching means that interrupts power supplied to a wiper motor when a wiper blade that is moving towards a return position has reached just-in-front of the return position.
In the wiper control device of Publication 1, the switching means interrupts power supply to the wiper motor just-in-front of the return position, such that the wiper blade is coasted thereby reducing irregular noise of returning of the wiper blade at the return position.
A wiper device and wiper control method are described in JP-A No. 2010-159044 (Publication 2) that prevent a wiper from flipping up under wind pressure due to motion wind by increasing the rotation force of a wiper motor when a speed of a vehicle increases to generate a strong motion wind.
In the wiper device and wiper control method of Publication 2, a sensor is disposed for detecting an rotation angle of an output shaft in a gear housing of a wiper motor, so as to enable detection of current position of a wiper blade that is swinging to-and-fro with forward and reverse rotation of a wiper motor. Moreover, in this wiper device and wiper control method, the rotation force of the wiper motor 18 is controlled according to the speed of the vehicle detected by a vehicle speed sensor so as to maintain the wiper blade in a lower return position.
FIG. 11 is a diagram illustrating a sensor signal angle that is a rotation angle detected by a sensor and the actual operation angle of an output shaft in an ordinary wiper device, such as that of the wiper device and wiper control method of Publication 2. In FIG. 11, configuration is made such that when the sensor signal angle reads 0°, the output shaft actual operation angle is also 0°, and the wiper blade is stopped at a stowing position provided at the lowest portion on the window glass when the output shaft actual operation angle is 0°.